We know that objects in motion have energy, but what happens to that energy when two things collide? Today we will be experimenting with marbles to answer questions about what happens when these collisions occur.
Next, I instruct student partners to get two small marble, two large marbles, a meter stick and their science notebooks for this activity. I tell students that they will practice with the marbles and observe what happens when the marbles collide. To keep the experiment fair, I demonstrate to students how to measure on the floor to mark where the "shooter marble" will be and then measure 40 centimeters to place tape where the "target marble" will rest. I instruct students to observe what happens when the marbles collide and to be specific about what they record in their science notebooks. Students also record how far the "target marble" travels after being hit with the "shooter marble." I display the directions for this marble lab on the board for all to see and then let students begin exploring. (Marble Lab)
You can see in this photo below a sample student science notebook. The student has recorded that when the small marble collided with the big marble, the big marble traveled 48 cm.
In the photo and videos below, you can watch students working together in order to collide their marbles.
You can see in these two videos below how excited and enthusiastic students are to "play" with and experiment with these colliding marbles. As I was watching and listening to students, it struck me how so many of them have never experimented with marbles or other objects that could collide into each other. Many of my students have lots of experience with video games, iPads, iPods, cell phones and other devices, but very few have experience with "old fashioned toys" like marbles. This simple hands one experience creates natural curiosity in my students that I strive for in every lesson. I was reminded how important it is to let students explore and use their hands as often as possible.
After about 15 minutes, I bring the class back together, and ask a student partner to demonstrate what they have discovered. I encourage students to use their own words to describe their findings. Then, I ask students to talk with each other about what they think happens to the energy in the first item when it collides with the second? (Kinetic energy transfers to the second object)
Next I discuss with the students the idea of collisions and energy. If a marble hits a stationary marble, the stationary marble begins to move off. Kinetic energy is said to transfer from one marble to the other. I briefly lead a class discussion about Newton's Law's of Motion by using this website: http://teachertech.rice.edu/Participants/louviere/Newton/law1.html
I allow students to change the distance of their "target marble" and "shooter marble" and observe if their results are similar. Students also work to finish their recordings in their science notebooks. Students work with their partners to complete the questions from the marble lab sheet. (marble lab)
Students turn in their notes for the day with a write up of their findings. The diagrams in the notebooks and their explanation of what they learned will help to show student understanding. As students worked on the marble collisions, I also informally assess their knowledge of energy and collisions by observing and asking guiding questions like:
What happens when the marbles collide?
What can you tell about the energy?
Does the collision change the motion of the marbles? How?